🔍 Key Concepts

• Self-elevating (jack-up) drilling unit operating conditions during normal transit • Difference between structural limits (legs, hull) and operational limits (stability, immersion, motions) • How wind speed relates to allowable motions and operating criteria

💭 Think About

• Ask yourself: During a normal transit with legs up, which part of the unit actually interacts with the sea state and limits how much it can move? • Consider which option is typically used as the primary design/operational criterion for how much a unit may roll, pitch, or heave during a normal voyage in moderate weather. • Think about when leg strength or deck-edge immersion would become the critical factor and whether that matches a <70-knot wind, normal-transit situation.

✅ Before You Answer

• Verify which factor is normally used to set allowable motions (roll, pitch, heave) for a mobile offshore drilling unit in transit. • Check whether leg strength is usually critical with legs fully raised during transit, or mainly during jacking and elevated operations. • Confirm when deck edge immersion becomes a limiting factor and whether that’s more of a flooding/freeboard issue than a motion criterion.